1. Field of the Invention
The invention relates to an image forming apparatus, which can execute a purge operation at high speed so as to restore ink ejection performance, and can downsize an entire apparatus including an ink receiving unit for receiving ink in the purge operation.
2. Description of the Related Art
Image forming apparatuses have been known in which recording heads corresponding to respective colors are arranged in parallel and ink is ejected onto a recording medium, which is being conveyed, from nozzles formed in the recording heads, to thereby form an image on the recording medium.
In such image forming apparatuses, ink lump or air is sometimes clogged in the nozzles, and then normal ink ejection performance is obstructed. Therefore, a purge operation is executed so as to restore ink ejection performance. For example, the purge operation is executed so that the ink lump or air clogged in the nozzles is removed from the nozzles to the outside by ejecting ink from the nozzles at an unusual great pressure. At this time, since ink is discharged together with the ink lump or air, the image forming apparatuses have an ink receiving unit that receives discharged ink.
Also, in this type of image forming apparatuses, in order to prevent ink in the nozzles from being dried when the apparatus is not used, a cap unit, which can abut against a nozzle formation surface of each recording head so as to form a closed space in which the nozzle formation surface is sealed up is provided.
U.S. Pat. No. 5,483,267 discloses such an image forming apparatus having the ink receiving unit and the cap unit.
The ink jet recording apparatus has four recording heads corresponding to four colors of cyan, magenta, yellow, and black. Further, an ink receiver has such a size as to cover one of the four recording heads. A cap caps the four recording heads simultaneously. In addition, the ink receiver and the cap are arranged in parallel. The ink receiver is reciprocated along the arrangement direction integrally with or independently of the cap.
According to U.S. Pat. No. 5,483,267, when capping, the cap and the ink receiver are integrally moved so that the cap is located at a predetermined capping position. Further, when performing the purge operation, the ink receiver is moved independently of the cap to a position where ink ejected from the recording head is received.